Multiplexing of physical sidelink control channel (PSCCH) and physical sidelink shared channel (PSSCH)

ABSTRACT

Sidelink vehicle-to-everything (V2X) transmission is performed over a Physical Sidelink Control Channel (PSCCH) and a Physical Sidelink Shared Channel (PSSCH). Encoded control information is transmitted in the PSCCH and encoded data is transmitted in the PSSCH. The PSCCH uses a first portion of the time-and-frequency resources, and the PSSCH uses and a second portion of the time-and-frequency resources. A first part of the PSSCH uses a first set of time resources overlapping with the PSCCH and a first set of frequency resources non-overlapping with the PSCCH. A second part of the PSSCH uses a second set of time resources non-overlapping with the PSCCH and a second set of frequency resources overlapping with the PSCCH.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.62/717,123 filed on Aug. 10, 2018, the entirety of which is incorporatedby reference herein.

TECHNICAL FIELD

Embodiments of the invention relate to wireless communications; morespecifically, to wireless communications between two user equipmentterminals (UEs).

BACKGROUND

5G New Radio (NR) is a telecommunication standard for mobile broadbandcommunications. 5G NR is promulgated by the 3rd Generation PartnershipProject (3GPP) to significantly improve on performance metrics such aslatency, reliability, throughput, etc.

Vehicle-to-Everything (V2X) communication has the potential to modernizemobile communications for vehicles and significantly reduce the numberof vehicular crashes and fatalities. Furthermore, V2X technologies canimprove traffic management and the safety of autonomous vehicles. V2Xtechnologies enable communications between vehicles as well ascommunications between a vehicle and other communication entities. NRV2X is built atop of 5G NR and is expected to support advanced V2Xapplications that require much more stringent Quality of Service (QoS)compared to applications supported by LTE-based V2X. For example, someof the NR V2X use-cases require the end-to-end latency to be as low as 3milliseconds with a reliability of 99.999%.

As such, there exists a need for further improvements in NR technologiesin order to meet the demand for mobile broadband access and thestringent QoS requirements.

SUMMARY

In one embodiment, a method is provided for sidelinkvehicle-to-everything (V2X) transmission. The method comprisestransmitting encoded control information in a Physical Sidelink ControlChannel (PSCCH) using a first portion of time-and-frequency resourcesassigned to the sidelink V2X communication, and transmitting encodeddata in a Physical Sidelink Shared Channel (PSSCH) using a secondportion of the time-and-frequency resources. A first part of the PSSCHuses a first set of time resources overlapping with the PSCCH and afirst set of frequency resources non-overlapping with the PSCCH, and asecond part of the PSSCH uses a second set of time resourcesnon-overlapping with the PSCCH and a second set of frequency resourcesoverlapping with the PSCCH.

In one embodiment, a transmit (Tx) user equipment (UE) operative toperform sidelink V2X transmission is provided. The Tx UE includes anantenna; a transceiver coupled to the antenna; one or more processorscoupled to the transceiver; and memory coupled to the one or moreprocessors. The one or more processors are operative to: identifytransmission parameters for communicating with a receive (Rx) UE; mapthe transmission parameters to time-and-frequency resources assigned tothe Tx UE for the sidelink V2X communication; encode control informationand data according to the transmission parameters; and transmit, via thetransceiver and the antenna, encoded control information in a PSCCH andencoded data in a PSSCH using a first portion and a second portion,respectively, of the time-and-frequency resources. A first part of thePSSCH uses a first set of time resources overlapping with the PSCCH anda first set of frequency resources non-overlapping with the PSCCH. Asecond part of the PSSCH uses a second set of time resourcesnon-overlapping with the PSCCH and a second set of frequency resourcesoverlapping with the PSCCH.

In another embodiment, an Rx UE operative to receive sidelink V2Xtransmission. The Rx UE includes an antenna; a transceiver coupled tothe antenna; one or more processors coupled to the transceiver; andmemory coupled to the one or more processors. The one or more processorsare operative to: decode received symbols for control information overone or more subchannels using blind detection; based on the controlinformation, identify a first portion and a second portion oftime-and-frequency resources used by a Tx UE as a PSCCH and a PSSCH,respectively, for the sidelink V2X transmission; and decode data in thePSSCH according to the control information in the PSCCH. A first part ofthe PSSCH uses a first set of time resources overlapping with the PSCCHand a first set of frequency resources non-overlapping with the PSCCH. Asecond part of the PSSCH uses a second set of time resourcesnon-overlapping with the PSCCH and a second set of frequency resourcesoverlapping with the PSCCH.

Other aspects and features will become apparent to those ordinarilyskilled in the art upon review of the following description of specificembodiments in conjunction with the accompanying figures.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is illustrated by way of example, and not by wayof limitation, in the figures of the accompanying drawings in which likereferences indicate similar elements. It should be noted that differentreferences to “an” or “one” embodiment in this disclosure are notnecessarily to the same embodiment, and such references mean at leastone. Further, when a particular feature, structure, or characteristic isdescribed in connection with an embodiment, it is submitted that it iswithin the knowledge of one skilled in the art to effect such feature,structure, or characteristic in connection with other embodimentswhether or not explicitly described.

FIG. 1 is a diagram illustrating a network in which the embodiments ofthe present invention may be practiced.

FIG. 2 is a diagram illustrating a concept of sidelink V2X communicationbetween two UEs according to one embodiment.

FIG. 3 is a diagram illustrating an example of time-and-frequencyresources allocated to a UE for sidelink V2X communication according toone embodiment.

FIG. 4A is a diagram illustrating further details of a resource gridaccording to one embodiment.

FIG. 4B is a diagram illustrating a resource grid with an alternativefrequency resources allocation for the PSCCH according to oneembodiment.

FIG. 4C is a diagram illustrating time-and-frequency resources used byreference signals according to one embodiment.

FIG. 4D is a diagram illustrating an alternative allocation oftime-and-frequency resources used by sidelink V2X communicationaccording to one embodiment.

FIGS. 5A and 5B illustrate methods for a transmit (Tx) UE to performsidelink V2X transmission according to one embodiment.

FIG. 6 illustrates a method for a receive (Rx) UE to receive sidelinkV2X transmission from a Tx UE according to one embodiment.

FIG. 7 is a block diagram illustrating elements of a UE configured toprovide sidelink V2X communication according to one embodiment.

DETAILED DESCRIPTION

In the following description, numerous specific details are set forth.However, it is understood that embodiments of the invention may bepracticed without these specific details. In other instances, well-knowncircuits, structures and techniques have not been shown in detail inorder not to obscure the understanding of this description. It will beappreciated, however, by one skilled in the art, that the invention maybe practiced without such specific details. Those of ordinary skill inthe art, with the included descriptions, will be able to implementappropriate functionality without undue experimentation.

In a vehicle-to-everything (V2X) wireless communication system, a UserEquipment (UE) may communicate directly with another UE via a sidelinkchannel, without using a base station as an intermediary. A sidelinkchannel may include a Physical Sidelink Control Channel (PSCCH) and aPhysical Sidelink Shared Channel (PSSCH). The PSCCH may be used tocommunicate control information, and the PSSCH may be used tocommunicate data. Embodiments of the methods and apparatuses describedherein improve the performance of sidelink V2X communication systems bymultiplexing the PSCCH and the PSSCH in time and frequency.

FIG. 1 is a diagram illustrating a network 100 in which the embodimentsof the present invention may be practiced. The network 100 is a wirelessnetwork which may be a 5G network, an NR network, and/or the like. Thenetwork 100 may include a number of base stations (BSs), such as BSs 120a, 120 b, and 120 c, collectively referred to as the BSs 120. In somenetwork environments such as an NR network, a BS may be known as agNodeB, a gNB, and/or the like. In an alternative network environment, aBS may be known by other names. Each BS 120 provides communicationcoverage for a particular geographic area known as a cell, such as acell 130 a, 130 b or 130 c. The radius of a cell size may range fromseveral kilometers to a few meters. A BS may communicate with one ormore other BSs or network entities directly or indirectly via a wirelessor wireline backhaul.

A network controller 110 may be coupled to a set of BSs such as the BSs120 to coordinate, configure, and control these BSs 120. The networkcontroller 110 may communicate with the BSs 120 via a backhaul.

The network 100 further includes a number of user equipment terminals(UEs), such as UEs 150 a-150 f, collectively referred to as the UEs 150.The UEs 150 may be anywhere in the network 100, and each UE 150 may bestationary or mobile. The UEs 150 may also be known by other names, suchas a mobile station, a subscriber unit, and/or the like. Some of the UEs150 may be implemented as part of a vehicle. Examples of the UEs 150 mayinclude a cellular phone (e.g., a smartphone), a wireless communicationdevice, a handheld device, a laptop computer, a cordless phone, atablet, a gaming device, a wearable device, an entertainment device, asensor, an infotainment device, Internet-of-Things (IoT) devices, or anydevice that can communicate via a wireless medium.

In some embodiments, two or more UEs 150 (e.g., UEs 150 a and 150 b; UEs150 d and 150 e; UEs 150 c and 150 f) may communicate directly viasidelink V2X communication, without using any of the BSs 120 as anintermediary to communicate with one another. For example, twocommunicating UEs may be in the coverage area of one or more BSs (e.g.,UEs 150 a and 150 b are in the coverage area of BS 120 a); one of thetwo communicating UEs may be in the coverage area of a BS 120 (e.g., UE150 c is in the coverage area of BS 120 c while UE 150 is not in thecoverage area of any BSs); or neither of the two communicating UEs is inthe coverage area of any BSs (e.g., both UEs 150 d and 150 e are outsidethe coverage area of BSs 120). These UEs 150 can be pre-configured toperform the sidelink V2X communication without the assistance from anyBSs, access points, or the like.

To simplify the discussion, the methods and apparatuses are describedwithin the context of NR. However, one of ordinary skill in the artwould understand that the methods and apparatuses described herein areapplicable generally to a variety of other wireless V2X communicationsystems.

Furthermore, it is noted that while the disclosed embodiments may bedescribed herein using terminology commonly associated with 5G or NRwireless technologies, the present disclosure can be applied to othermulti-access technologies and the telecommunication standards thatemploy these technologies.

FIG. 2 is a diagram illustrating a concept of sidelink V2X communicationbetween a transmit (Tx) UE 250 a and a receive (Rx) UE 250 b accordingto one embodiment. The Tx UE 250 a and the Rx UE 250 b may be examplesof the UE 150 a and the UE 150 b, respectively, in FIG. 1. In oneembodiment, the Tx UE 250 a and the Rx UE 250 b may be wireless deviceslocated in corresponding vehicles. In another embodiment, the Rx UE 250b may be a wireless device located in an entity connected to a wirelessnetwork, such as the network 100 in FIG. 1.

Before the Tx UE 250 a transmits data to the Rx UE 250 b, the Tx UE 250a first obtains time resources (i.e., one or more time slots, or“slots”) and frequency resources (i.e., one or more resource blocks(RBs) within subchannels) for the sidelink V2X communication. The timeresources and the frequency resources may be collectively referred to asthe time-and-frequency resources. In some cases, a BS (e.g., one of theBSs 120 in FIG. 1) may select available time-and-frequency resources forthe Tx UE 250 a. In some cases, the Tx UE 250 a may selecttime-and-frequency resources based on information indicating, at leastin part, availability of the resources. Once the Tx UE 250 a obtains thenecessary time-and-frequency resources, the Tx UE 250 a transmitscontrol information in a PSCCH 220 and data in the PSSCH 230 to the RxUE 250 b. As the control information in the PSCCH 220 is used to decodethe data in the PSSCH 230, the PSSCH 230 is said to be associated withthe PSCCH 220.

In some embodiments, a sidelink channel 210 may be established betweenthe Tx UE 250 a and the Rx UE 250 b. For example, the PSCCH 220 maycarry Sidelink Control Information (SCI), which may indicate varioustransmission parameters for transmitting data to the Rx UE 250 b in thePSSCH 230. The transmission parameters may include one or more of: amodulation and coding scheme (MCS), the number of RBs in frequency, thenumber of time slots. Additional information may also be included.

The Rx UE 250 b obtains the V2X transmission parameters by decoding theSCI in the PSCCH 220. According to the parameters, the Rx UE 250 b candecode the data in the PSSCH 230. In some prior systems that provideLong-Term Evolution (LTE)-based V2X communication, the PSCCH and thePSSCH are multiplexed in frequency only. That is, control informationand data are transmitted concurrently in different frequencies. Onedrawback of these prior systems is that a receiver generally has tobuffer the control information for one or more time slots and can decodethe data only after the control information is received completely. Dueto tight latency constraints in NR V2X, the PSCCH 220 and the PSSCH 230described herein may be multiplexed both in time and in frequency.Details of the multiplexing are provided below with reference to theexamples shown in FIG. 3 and FIGS. 4A-4D.

FIG. 3 is a diagram illustrating an example of time-and-frequencyresources allocated to a UE (e.g., the Tx LE 250 a in FIG. 2) forsidelink V2X communication according to one embodiment. A resource grid300 represents tune-and-frequency resources, with the time axis in thehorizontal direction and the frequency axis in the vertical direction.Each square in the resource grid 300 represents a time resource of oneslot and a frequency resource of one subchannel.

Multiple time and frequency configurations are supported by NR. Withrespect to time resources, a frame may be 10 ms in length, and may bedivided into ten subframes of 1 ms each. Each subframe may be furtherdivided into multiple equal-length time slots (also referred to asslots), and the number of slots per subframe may be different indifferent configurations. Each slot may be further divided into multipleequal-length symbol durations (also referred to as symbols); e.g., 7 or14 symbols. With respect to frequency resources, NR supports multipledifferent subcarrier bandwidths. Contiguous subcarriers are grouped intoone resource block (RB). In one configuration, one RB contains 12subcarriers, also referred to as resource elements (REs). Multiple RBsform one subchannel.

Within a time slot, there may be one or more subchannels and one or moreslots allocated to sidelink V2X communication. In the example of FIG. 3,the Tx UE 250 a may select, or be assigned, four slots and threesubchannels for transmitting control information and data to the Rx UE250 b. The slots and subchannels used by the Tx UE 250 a may bespecified by their respective starting positions and lengths (e.g.,Start_slot, L_slot, Start_subCH, and L_subCH, where L stands for“length”). The three-by-four squares in the resource grid 300 is hereinreferred to as a region 310, which represents the time-and-frequencyresources used by the Tx UE 250 a for sidelink V2X transmission; morespecifically, for use as the PSCCH 220 (shown in an oblique-linedpattern) and the PSSCH 230 (shown in a dotted pattern).

FIG. 3 shows that the region 310 is formed by contiguous slots andcontiguous subchannels. The PSCCH 220 occupies an initial portion of thefirst slot (i.e., Start_slot), and covers a partial portion of the firstsubchannel (i.e., Start_subCH), the entire second subchannel, and apartial portion of the third subchannel. In one embodiment, the PSSCH230 occupies the region 310 that is not occupied by the PSCCH 220; thatis, the region 310 includes only the PSCCH 220 and the PSSCH 230. Inanother embodiment, the region 310 may include the PSCCH 220, the PSSCH230, and reference signals for measuring and calibrating signal strengthin the PSCCH 220 and/or the PSSCH 230; e.g., by performing automaticgain control (AGC).

FIG. 4A is a diagram illustrating further details of a resource gridaccording to one embodiment. FIG. 4A shows a resource grid 400, whichmay be formed by the beginning slot (i.e., Start_slot) of the resourcegrid 300 and five subchannels starting from Start_subCH of the resourcegrid 300. Each slot includes 14 Orthogonal Frequency-DivisionMultiplexing (OFDM) symbols. Each subchannel is divided into multiple(e.g., 4) concurrent RBs, and each RB spans one symbol duration. An RBmay contain multiple (e.g., 12) equal-spaced REs (i.e., subcarriers,which are not shown in FIG. 4A). The resource grid 400 representstime-and-frequency resources for sidelink V2X communication. The basicunit of resource in the resource grid 400 is an RB of one symbolduration, which is also referred to as an RB-symbol unit.

In this embodiment, a number of contiguous and concurrent RBs thatoccupy the first two symbols in time is designated as a PSCCH 420 (shownin an oblique-lined pattern) for carrying control information includingthe SCI. The number of symbols used by a PSCCH may be specified by anetwork system according to the NR specification. The PSCCH 420 may bean example of the PSCCH 220 in FIGS. 2 and 3. The SCI carried in thePSCCH 420 may be decoded by an Rx UE to identify a PSSCH associated withthe PSCCH 420; FIG. 4A shows the PSSCH as being composed of a first partof PSSCH 430 a and a second part of PSSCH 430 b, collectively referredto as the PSSCH 430. In FIG. 4A, each basic unit of resource (i.e.,which is an RB-symbol unit shown as one of the smallest squares in thegrid 400) in the first part of PSSCH 430 a is marked “1” with a dottedbackground, and each basic unit of resource (i.e., an RB-symbol unit) inthe second part of PSSCH 430 b is shown with the dotted backgroundwithout the additional “1” mark.

In FIG. 4A, the PSCCH 420 and its associated PSSCH 430 together form aregion 410 in the resource grid 410. The region 410 is formed bycontiguous symbols in time and contiguous RBs in frequency; morespecifically, the region 410 is formed by the bottom 12 rows of RBs for14 symbols duration, or equivalently, the bottom three subchannels forone slot duration. The region 410 has the same starting RB for eachsymbol, and extends in frequency over the same number RBs for eachsymbol. In the embodiment of FIG. 4A, the region 410 contains only thePSCCH 420 and its associated PSSCH 430. In another embodiment, a regionin the resource grid 410 allocated to sidelink V2X communication maycontain a PSCCH, its associated PSSCH, and reference signals formeasuring and calibrating the PSCCH and/or its associated PSSCH.

In one embodiment, the basic units of resource used by the PSSCH 430follow a frequency-first order; that is, in every symbol duration of thePSSCH 430 (including the first part 430 a and the second part 430 b),data is filled by the Tx UE and processed by the Rx UE from the lowestfrequency to the highest frequency, as indicated by the dotted arrows(only three dotted arrows are shown for simplicity). In one embodiment,the PSCCH 420 may also follow the frequency-first order; that is, inevery symbol duration of the PSSCH 420, control information is filled bythe Tx UE and processed by the Rx UE from the lowest frequency to thehighest frequency.

In the embodiment of FIG. 4A, the first part of PSSCH 430 a uses a firstset of time resources (i.e., the leftmost two symbols) overlapping withthe symbols used by the PSCCH 420, and also uses a first set offrequency resources (i.e., the 1^(st), 2^(nd), 10^(th), 11^(th), and12^(th) RBs from the bottom) non-overlapping with the frequencies of thePSCCH 420. Thus, the PSCCH 420 and the first part of PSSCH 430 a may befrequency-multiplexed.

In the embodiment of FIG. 4A, the second part of PSSCH 430 b uses asecond set of time resources (i.e., the rightmost twelve symbols)non-overlapping with the symbols used by the PSCCH 420. Thus, the PSCCH420 and the second part of PSSCH 430 b may be time-multiplexed. Thesecond part of PSSCH 430 b also uses a second set of frequency resources(i.e., the bottom three subchannels) overlapping with the frequencies ofthe PSCCH 420.

In other words, the PSCCH 420 may be transmitted in a first time periodin first frequencies. The first part of PSSCH 430 a may be transmittedin the first time period in second frequencies, where the firstfrequencies and the second frequencies are non-overlapping frequencies.The second part of PSSCH 430 b is transmitted in a second time periodimmediately following the first time period in a contiguous frequencyrange which includes the first frequencies and the second frequencies.

It is noted that the time-and-frequency resources used by the PSCCH 420and the PSSCH 430 are formed by one or more contiguous slots ofcontiguous symbols in time and one or more contiguous RBs of contiguoussubcarriers in frequency. Furthermore, the time-and-frequency resourcesallocated to the PSCCH 420 is formed by contiguous frequency resources(e.g., RBs) and contiguous time resources (e.g., symbols).

The term “overlapping,” as used herein with respect to frequency and/ortime, refers to “completely overlapping in frequency and/or time.” Forexample, when channel A and channel B use overlapping time resources, itmeans one of the following scenarios: channel A and channel B span overexactly the same time duration; the entire time duration of channel A isa fraction of the entire time duration of channel B; or the entire timeduration of channel B is a fraction of the entire time duration ofchannel A. Similarly, when channel A and channel B use overlappingfrequency resources, it means one of the following scenarios: channel Aand channel 13 span over exactly the same frequency range; the entirefrequency range of channel A is a fraction of the entire frequency rangeof channel B, or the entire frequency range of channel B is a fractionof the entire frequency range of channel A.

The term “non-overlapping,” as used herein with respect to frequencyand/or time, refers to “no common time duration and/or no commonfrequency range.” However, when channel A and channel B usenon-overlapping time/frequency resources, channel A and channel B mayshare the same boundary in time/frequency. For example, when channel Aand channel B use non-overlapping time resources, channel A mayimmediately follow the last symbol of channel B, or may immediatelyprecede the first symbol of channel B in time. As another example, whenchannel A and channel B use non-overlapping frequency resources, channelA may immediately follow the last RB of channel B, or may immediatelyprecede the first RB of channel B in frequency.

FIG. 4B is a diagram illustrating the resource grid 400 with analternative frequency resources allocation for a PSCCH 422 according toone embodiment. In FIG. 4B, the same region 410 of time-and-frequencyresources is allocated to a Tx UE for sidelink V2X transmission as inFIG. 4A. The PSCCH 422 uses the same number of time-and-frequencyresources (i.e., the same number of RB-symbol units in the resource grid400) as the PSCCH 420 in FIG. 4A. However, the PSCCH 422 and the PSCCH420 (FIG. 4A) has different starting RBs in frequency; morespecifically, the PSCCH 422 is the PSCCH 420 shifted down by two RBs infrequency.

FIG. 4B shows that the starting RB of a PSCCH may be the same as thestarting RB of its associated PSSCH, while FIG. 4A shows that thestarting RB of a PSCCH may be shifted up from the starting RB of itsassociated PSSCH. In one embodiment, the starting frequency of a PSCCHmay be k RBs away from the starting frequency of its associated PSSCH,where k is a non-negative integer configurable by the network system.

The PSSCH associated with the PSCCH 422 is shown in FIG. 4B as a firstpart of PSSCH 432 a and a second part of PSSCH 432 b. The second part ofthe PSSCH 432 b uses the same time-and-frequency resources as the secondpart of PSSCH 430 b (FIG. 4A). The first part PSSCH 432 a uses RBs thatimmediately follow the RBs used by its associated PSCCH 422.

FIG. 4C is a diagram illustrating time-and-frequency resources used byreference signals according to yet another embodiment. In FIG. 4C, thesame region 410 of time-and-frequency resources is allocated to a Tx UEfor sidelink V2X transmission as in FIG. 4A and FIG. 4B. However, inaddition to a PSCCH 424 and its associated PSSCH (shows as a first partof PSSCH 434 a and a second part of PSSCH 434 b), the region 410 alsoincludes time-and-frequency resources allocated to reference signalsused to measure and/or calibrate the PSCCH 424 and/or its associatedPSSCH. In the embodiment of FIG. 4C, the starting symbol of the PSCCH424 in the slot is the second symbol (as the first symbol is allocatedto the reference signals). In some embodiments, the starting symbol of aPSCCH in the starting slot (i.e., Start_slot) is configurable by thenetwork system; e.g., the starting symbol may be the first symbol or thesecond symbol in Start_slot).

FIG. 4D is a diagram illustrating an alternative allocation oftime-and-frequency resources used by sidelink V2X communicationaccording to yet another embodiment. In some cases, the sub-region thatimmediately follows a PSCCH 426 in time and shares the same RBs infrequency as the PSCCH 426 has sufficient time-and-frequency resourcesfor transmitting the encoded data. In these cases, the sub-region isused as a PSSCH 436 which is associated with the PSCCH 426. The PSSCH436 uses a set of time resources non-overlapping with the PSCCH 426 anda set of frequency resources overlapping with the PSCCH 426. Thus, thePSCCH 426 and the PSSCH 436 may be time-multiplexed. It is noted thateven if the data may be encoded to use less than the sub-region ofresources assigned to the PSSCH 436, the PSSCH 436 is still assigned thesame number of RBs as the PSCCH 426. In some embodiments, redundancy orextra data encoding may be applied to the data so that the encoded datacan occupy the entire PSSCH 436, which uses the entire frequency rangeof the PSCCH 426 and the set of time resources non-overlapping with thePSCCH 426.

It is noted that the multiplexing of the PSCCH and the PSSCH is notlimited to the aforementioned examples. For example, the number of RBsin a subchannel may be different in alternative embodiments, and thenumber of symbols and the number of RBs occupied by the PSCCH may bedifferent in alternative embodiments. The size of the region allocatedto the PSCCH and the PSSCH may also be different in alternativeembodiments.

The multiplexing of the PSCCH and the PSSCH described herein may includeboth time-division multiplexing (TDM) and frequency-divisionmultiplexing (FDM). Unlike a conventional FDM-only design in which an RxUE cannot start to decode the PSSCH until the end of a slot, themultiplexing methods described herein enables the Rx UE to startdecoding the PSSCH as soon as a small number of symbols (e.g., 1, 2 or3) containing the SCI in the PSCCH is decoded. Furthermore, according tothe multiplexing methods described herein. Rx UEs can power down for therest of a transmission time interval (TTI) if the UEs learn fromdecoding the PSCCHs that they are not scheduled for that TTI.

The multiplexing methods described herein improve resource efficiency.Within the time-and-frequency resources used by the sidelink V2Xtransmission, a Tx UE uses all frequency resources in every symbolwithin a TTI (e.g., a slot). Thus, resource efficiency is achieved sinceall frequency resources within the available time duration are utilized.

The multiplexing methods described herein include frequency-multiplexingof the PSCCH and the PSSCH, thereby enabling the PSSCH to start at thesame time as the PSCCH and in non-overlapping frequencies. Themultiplexing methods described herein further include time-multiplexingof the PSCCH and the PSSCH, thereby enabling the PSSCH to continue afterthe PSCCH ends in time, using overlapping frequencies with the PSCCH.

A PSCCH and its associated PSSCH for sidelink V2X communication have oneor more of the following characteristics. In one embodiment, the numberof symbols used by the PSCCH is configurable; e.g., one, two, or threesymbols. The number of RBs used by the PSCCH is also configurable andcan be independent of the number of RBs in a subchannel. The PSCCH mayextend in time over one or more symbols (e.g., 1, 2 or 3 symbols), andmay extend in frequency over any number of RBs, where this number of RBsmay be less, or more, than the number of RBs in a sub-channel. The PSCCHis composed of contiguous symbols and contiguous RBs. The startingsymbol of the PSCCH in a slot is configurable and can be the first orthe second symbol of the starting slot (i.e., Start_slot). The startingRB position of the PSCCH is k RBs away from the starting RB position ofthe PSSCH, where k≥0. The starting and ending positions of the PSCCH mayor may not be aligned with the subchannel boundaries.

The time-and-frequency resources used by the PSCCH and its associatedPSSCH have one or more of the following characteristics. Thetime-and-frequency resources used by the PSCCH and the PSSCH are formedby one or more contiguous slots of contiguous symbols in time and one ormore contiguous RBs of contiguous subcarriers in frequency. Thetime-and-frequency resources allocated to the PSCCH is formed bycontiguous frequency resources and contiguous time resources. Within thetime-and-frequency resources, the set of REs in each symbol areidentical. In one embodiment, a portion of the time-and-frequencyresources is allocated to the PSCCH and the rest of time-frequencyresources is allocated to its associated PSSCH. In one embodiment,within the time-frequency resources, every RE is used by the PSCCH, theassociated PSSCH, or reference signals for the PSCCH and the PSSCH. Thefrequency resources used by the PSSCH are at least as large as thefrequency resources used by the PSCCH.

In one embodiment, the time-and-frequency resources used by the PSCCHand/or PSSCH follow the frequency-first order, an example of which isshown and described in connection with FIG. 4A. The frequency-firstorder is applicable to the examples in FIGS. 4B, 4C and 4D, as well asother scenarios of time-and-frequency usage with both TDM and FDM of thePSCCH and the PSSCH.

FIGS. 5A and 5B illustrate methods 500 and 501 for a Tx UE to performsidelink V2X transmission according to one embodiment. The method 500may be performed by the UE 150 a and/or UE 150 b of FIG. 1 and/or the UE700 of FIG. 7 in some embodiments. The method 500 starts at step 510when the UE identifies transmission parameters for communicating with anRx UE. The UE at step 520 maps the transmission parameters totime-and-frequency resources assigned to the UE for the V2Xtransmission. The UE at step 530 encodes control information and dataaccording to the transmission parameters.

After step 530, the process of sidelink V2X transmission proceeds tostep 540 of method 501 in FIG. 5B. The UE (i.e. the Tx UE) at step 540transmits the encoded control information in a PSCCH using a firstportion of the time-and-frequency resources assigned to the V2Xtransmission. The UE at step 550 transmits encoded data in a PSSCH usinga second portion of the time-and-frequency resources. In someembodiments, step 540 and step 550 may be performed in any order intime, such as sequentially, in parallel or partially in parallel.

With respect to the PSCCH and the PSSCH, a first part of the PSSCH usesa first set of time resources overlapping with the PSCCH and a first setof frequency resources non-overlapping with the PSCCH. A second part ofthe PSSCH uses a second set of time resources non-overlapping with thePSCCH and a second set of frequency resources overlapping with thePSCCH.

In one embodiment, the time-and-frequency resources are described by aregion of a resource grid, wherein the region is formed by contiguousRBs in frequency and contiguous time slots. In one embodiment, thetransmission parameters include one or more of: a modulation and codingscheme (MCS), the number of resource blocks (RBs), and the number oftime slots for the V2X transmission.

FIG. 6 illustrates a method 600 for a receive (Rx) UE to receivesidelink V2X transmission from a Tx UE according to one embodiment. Themethod 600 may be performed by the UE 150 a and/or UE 150 b of FIG. 1and/or the UE 700 of FIG. 7 in some embodiments. The method 600 startsat step 610 when the Rx UE decodes received symbols for controlinformation over one or more subchannels using blind detection. Based onthe control information, the Rx UE at step 620 identifies a firstportion and a second portion of time-and-frequency resources used by theTx UE as a PSCCH and a PSSCH, respectively, for the sidelink V2Xtransmission. The destination UE at step 630 decodes data in the PSSCHaccording to the control information in the PSCCH.

In one embodiment, the time-and-frequency resources, the PSCCH, and thePSSCH mentioned in the method 600 may be the same as those mentioned inthe method 501 of FIG. 5B. In one embodiment, the Rx UE may perform themethod 501 except that “transmit” is replaced by “receive.”

For example, an Rx UE may check a set of sub-channels in a predeterminedfrequency range at the beginning of a slot. The set of sub-channels maybe contiguous in frequency. The Rx UE may perform blind detection toconcurrently decode the symbols in each sub-channel to determine whetherthere is data in transmission for which it is the intended recipient.The Rx UE also buffers the received symbols in the set of sub-channelsbefore the Rx UE successfully makes the determination. When the Rx UEdecodes SCI in a PSCCH for which it is the intended recipient, the Rx UEfrom the decoded SCI identities the starting symbol and the starting RBof the associated PSSCH, as well as the number of symbols (or slots) andthe number of RBs (or sub-channels) in the associated PSSCH. Some of thedata in the PSSCH may be buffered by the Rx UE before the SCI wassuccessfully decoded. The Rx UE can start decoding the data in the PSSCHas soon as the SCI is decoded.

FIG. 7 is a block diagram illustrating elements of a UE 700 (alsoreferred to as a wireless device, a wireless communication device, awireless terminal, etc.) configured to provide sidelink V2Xcommunication according to one embodiment. As shown, the UE 700 mayinclude an antenna 710, and a transceiver circuit (also referred to as atransceiver 720) including a transmitter and a receiver configured toprovide uplink and downlink radio communications with a base station ofa radio access network, and to provide sidelink V2X communicationsdirectly with other wireless devices. The UE 700 may also include aprocessor circuit (which is shown as a processor 730 and which mayinclude one or more processors) coupled to the transceiver 720. Theprocessor(s) 730 may include one or more processor cores. The UE 700 mayalso include a memory circuit (also referred to as memory 740) coupledto the processor 730. The memory 740 may include computer-readableprogram code that when executed by the processor 730 causes theprocessor 730 to perform operations according to embodiments disclosedherein. The UE 700 may also include an interface (such as a userinterface). The UE 700 may be incorporated in a vehicle or otherwireless devices operable to perform sidelink V2X communication. It isunderstood the embodiment of FIG. 7 is simplified for illustrationpurposes. Additional hardware components may be included.

Although the UE 700 is used in this disclosure as an example, it isunderstood that the methodology described herein is applicable to anycomputing and/or communication device capable of sidelink V2Xcommunication.

The operations of the flow diagrams of FIGS. 5A, 5B and 6 have beendescribed with reference to the exemplary embodiments of FIGS. 1 and 7.However, it should be understood that the operations of the flowdiagrams of FIGS. 5A, 5B and 6 can be performed by embodiments of theinvention other than the embodiments of FIGS. 1 and 7, and theembodiments of FIGS. 1 and 7 can perform operations different than thosediscussed with reference to the flow diagrams. While the flow diagramsof FIGS. 5A, 5B and 6 show a particular order of operations performed bycertain embodiments of the invention, it should be understood that suchorder is exemplary (e.g., alternative embodiments may perform theoperations in a different order, combine certain operations, overlapcertain operations, etc.).

Various functional components or blocks have been described herein. Aswill be appreciated by persons skilled in the art, the functional blockswill preferably be implemented through circuits (either dedicatedcircuits, or general purpose circuits, which operate under the controlof one or more processors and coded instructions), which will typicallycomprise transistors that are configured in such a way as to control theoperation of the circuity in accordance with the functions andoperations described herein.

While the invention has been described in terms of several embodiments,those skilled in the art will recognize that the invention is notlimited to the embodiments described, and can be practiced withmodification and alteration within the spirit and scope of the appendedclaims. The description is thus to be regarded as illustrative insteadof limiting.

What is claimed is:
 1. A method for sidelink vehicle-to-everything (V2X)transmission, comprising: transmitting, from a first user equipment (UE)to a second UE, encoded control information in a Physical SidelinkControl Channel (PSCCH) using a first portion of time-and-frequencyresources assigned to the sidelink V2X communication between the firstUE and the second UE; and transmitting, from the first UE to the secondUE, encoded data in a Physical Sidelink Shared Channel (PSSCH) using asecond portion of the time-and-frequency resources, wherein thetime-and-frequency resources are bounded by two subchannel boundaries ina frequency domain and two slot boundaries in a time domain, the PSCCHcarries Sidelink Control Information (SCI) indicating transmissionparameters for the second UE to decode the encoded data in a first partand a second part of the PSSCH, and wherein the first part of the PSSCHuses a first set of time resources overlapping with the PSCCH and afirst set of frequency resources non-overlapping with the PSCCH, thesecond part of the PSSCH uses a second set of time resourcesnon-overlapping with the PSCCH and a second set of frequency resourcesoverlapping with the PSCCH, the first part and the second part of thePSSCH are aligned in the frequency domain with at least one of the twosubchannel boundaries, and a frequency domain boundary between the PSCCHand first part of the PSSCH is not aligned with a subchannel boundary.2. The method of claim 1, further comprising: transmitting the firstpart of the PSSCH and the PSCCH by frequency-division multiplexing(FDM); and transmitting the second part of the PSSCH and the PSCCH bytime-division multiplexing (TDM).
 3. The method of claim 1, furthercomprising: transmitting the PSCCH in a first time period in firstfrequencies; transmitting the first part of the PSSCH in the first timeperiod in second frequencies, the first frequencies and the secondfrequencies being non-overlapping frequencies; and transmitting thesecond part of the PSSCH in a second time period immediately followingthe first time period in a contiguous frequency range which includes thefirst frequencies and the second frequencies.
 4. The method of claim 1,wherein the PSSCH is allocated with an entire frequency range of thePSCCH and the second set of time resources non-overlapping with thePSCCH when such allocation provides sufficient time-and-frequencyresources for transmitting the encoded data.
 5. The method of claim 1,wherein the time-and-frequency resources used by the PSCCH and the PSSCHare formed by one or more contiguous slots of contiguous symbols in timeand one or more contiguous resource blocks (RBs) of contiguoussubcarriers in frequency.
 6. The method of claim 1, wherein the firstportion of the time-and-frequency resources allocated to the PSCCH isformed by contiguous frequency resources and contiguous time resources.7. The method of claim 1, wherein the time-and-frequency resourcesinclude only the first portion allocated to the PSCCH and the secondportion allocated to the PSSCH.
 8. The method of claim 1, wherein thetime-and-frequency resources include the first portion allocated to thePSCCH, the second portion allocated to the PSSCH, and a remainingportion wherein the remaining portion is allocated to reference signalsassociated with the PSCCH and the PSSCH.
 9. The method of claim 1,wherein the PSCCH occupies a configurable number of symbols and aconfigurable number of RBs, and the configurable number of RBs used bythe PSCCH is independent of the number of RBs in a subchannel.
 10. Themethod of claim 1, wherein a starting symbol position of the PSCCH is aconfigurable number of symbols away from a time slot boundary, and astarting RB position of the PSCCH is a configurable number of RBs awayfrom a starting RB position of the PSSCH.
 11. The method of claim 1,wherein the time-and-frequency resources used by the PSSCH follow afrequency-first order in which data in the PSSCH is processed from alowest frequency to a highest frequency for every symbol.
 12. A transmit(Tx) user equipment (UE) operative to perform sidelinkvehicle-to-everything (V2X) transmission, comprising: an antenna; atransceiver coupled to the antenna; one or more processors coupled tothe transceiver; and memory coupled to the one or more processors,wherein the one or more processors are operative to: identifytransmission parameters for communicating with a receive (Rx) UE; mapthe transmission parameters to time-and-frequency resources assigned tothe Tx UE for the sidelink V2X communication between the Tx UE and theRx UE; encode control information and data according to the transmissionparameters; and transmit, via the transceiver and the antenna, to the RxUE encoded control information in a Physical Sidelink Control Channel(PSCCH) and encoded data in a Physical Sidelink Shared Channel (PSSCH)using a first portion and a second portion, respectively, of thetime-and-frequency resources, wherein the time-and-frequency resourcesare bounded by two subchannel boundaries in a frequency domain and twoslot boundaries in a time domain, the PSCCH carries Sidelink ControlInformation (SCI) indicating transmission parameters for the Rx UE todecode the encoded data in a first part and a second part of the PSSCH,and wherein the first part of the PSSCH uses a first set of timeresources overlapping with the PSCCH and a first set of frequencyresources non-overlapping with the PSCCH, the second part of the PSSCHuses a second set of time resources non-overlapping with the PSCCH and asecond set of frequency resources overlapping with the PSCCH, the firstpart and the second part of the PSSCH are aligned in the frequencydomain with at least one of the two subchannel boundaries, and afrequency domain boundary between the PSCCH and first part of the PSSCHis not aligned with a subchannel boundary.
 13. The Tx UE of claim 12,wherein the transceiver is operative to transmit the first part of thePSSCH and the PSCCH by frequency-division multiplexing (FDM), and totransmit the second part of the PSSCH and the PSCCH by time-divisionmultiplexing (TDM).
 14. The Tx UE of claim 12, wherein the PSSCH isallocated with an entire frequency range of the PSCCH and the second setof time resources non-overlapping with the PSCCH when such allocationprovides sufficient time-and-frequency resources for transmitting theencoded data.
 15. The Tx UE of claim 12, wherein the time-and-frequencyresources used by the PSCCH and the PSSCH are formed by one or morecontiguous slots of contiguous symbols in time and one or morecontiguous resource blocks (RBs) of contiguous subcarriers in frequency.16. The Tx UE of claim 12, wherein the first portion of thetime-and-frequency resources allocated to the PSCCH is formed bycontiguous frequency resources and contiguous time resources.
 17. The TxUE of claim 12, wherein the transmission parameters include one or moreof: a modulation and coding scheme (MCS), the number of RBs, and thenumber of time slots for the sidelink V2X transmission.
 18. A receive(Rx) user equipment (UE) operative to receive sidelinkvehicle-to-everything (V2X) transmission, comprising: an antenna; atransceiver coupled to the antenna; one or more processors coupled tothe transceiver; and memory coupled to the one or more processors,wherein the one or more processors are operative to: decode receivedsymbols for control information over one or more subchannels using blinddetection; based on the control information, identify a first portionand a second portion of time-and-frequency resources used by a transmit(Tx) UE as a Physical Sidelink Control Channel (PSCCH) and a PhysicalSidelink Shared Channel (PSSCH), respectively, for the sidelink V2Xtransmission between the Tx UE and the Rx UE; and decode data in thePSSCH according to the control information in the PSCCH, wherein thetime-and-frequency resources are bounded by two subchannel boundaries ina frequency domain and two slot boundaries in a time domain, the PSCCHcarries Sidelink Control Information (SCI) indicating transmissionparameters for the Rx UE to decode the data in a first part and a secondpart of the PSSCH, and wherein the first part of the PSSCH uses a firstset of time resources overlapping with the PSCCH and a first set offrequency resources non-overlapping with the PSCCH, the second part ofthe PSSCH uses a second set of time resources non-overlapping with thePSCCH and a second set of frequency resources overlapping with thePSCCH, the first part and the second part of the PSSCH are aligned inthe frequency domain with at least one of the two subchannel boundaries,and a frequency domain boundary between the PSCCH and first part of thePSSCH is not aligned with a subchannel boundary.
 19. The Rx UE of claim18, wherein the transceiver is operative to receive the first part ofthe PSSCH and the PSCCH by frequency-division multiplexing (FDM), and toreceive the second part of the PSSCH and the PSCCH by time-divisionmultiplexing (TDM).
 20. The Rx UE of claim 18, wherein thetime-and-frequency resources used by the PSCCH and the PSSCH are formedby one or more contiguous slots of contiguous symbols in time and one ormore contiguous resource blocks (RBs) of contiguous subcarriers infrequency.